The Hybridoma Core Facility will be used by approximately 30 UM-MAC investigators who are pursuing a variety of research projects that require monoclonal antibodies. The hybridoma Facility (HF) is a research laboratory, the purpose of which is to generate somatic-cell hybrids (hybridomas) that produce monoclonal antibodies of desired specificity. It is supported by the Michigan Diabetes Research and Training Center (MDRTC), and by the University of Michigan Multipurpose Arthritis Center (UM-MAC), for use by investigators within these centers, currently at a 10% recharge. It is also used by other investigators on a full recharge basis. Services include immunization of mice, fusion of B lymphocytes with myeloma cells to create hybridomas, subcloning and cryopreservation of hybridomas, antibody isotyping and production of ascites in mice. Consultation is available from the Hybridoma Core directors in design of immunization strategies and screening assays to ensure efficient detection of the desired monoclonal antibodies. The majority of hybridomas produced in the core are of murine origin, but rat, hamster and human hybridomas have also been produced. Since its establishment in 1980 the Hybridoma Facility has produced monoclonal antibodies against a wide variety of lymphocyte surface antigens, tumor cell antigens, purified proteins, hormones, hormone receptors and recombinant proteins. In the past four years of UM-MAC support (1993-1996) more than 65 fusions were performed for UM-MAC investigators. Subcloning was performed for more than 350 hybridomas and almost 400 monoclonal antibody batches were produced in murine ascites. A variety of specialized procedures have been added during the current funding cycle to address various needs of UM-MAC investigators. The current proposal will allow this facility to continue to provide up- to-date hybridoma technology for UM-MAC laboratories. The core will also provide collaborative and consultive services for the UM-MAC vector core in assisting investigators who may wish to select recombinant antibody- like reagents from phage display libraries. Through these initiatives, the Hybridoma Core will remain on the cutting edge of monoclonal antibody technology, and continue to provide optimal service to UM-MAC investigators.